In the process for manufacturing a Thin Film Transistor-Liquid Crystal Display (TFT-LCD), it's usually required to create a circuit pattern on an array substrate by using patterning technology. Developing is one significant process in the patterning technology, and the exposed pattern can only be presented with the action of the developer solution. The developer solution, through some chemical reactions, can etch away a portion of the photoresist on a transparent substrate which is not needed for the pattern formed by exposure with a mask plate. To guarantee the developing effect, the quality of the developer solution plays a very important role, however, in majority of the existing developing systems, the developer solution is used in a recycling way, and thus as the using times of the developer solution increases, the developer solution would be gradually contaminated and thus the developing effect degrade obviously. In order to ensure quality of developer solution, some of the manufacturers directly discharge the developer solution after it is used only once or a few times, which, although improves the product yield, reduces recycling times, increases the amount of the used developer solution, and thus increases cost of products. In order to ensure product yield while improving usage of the developer solution, it's possible to make real-time monitoring of developing effect of the developer solution during the course of recycling the developer solution, and make a dynamical regulation of the concentration of the developer solution to reach a better developing effect. In prior art, monitoring the quality of the developer solution may be mainly realized by measuring a concentration of the developer solution and a concentration of a certain component of the photoresist. However, as different developer solutions have component mixing ratios different from each other, and existing systems for monitoring developer solution perform monitoring on multiple components in the developer solution, it's difficult to report developing effect of the developer solution intuitively and accurately. When a system for monitoring developer solution can not intuitively and effectively evaluate developing effect of developer solution, it's inevitable to waste developer solution or cause poor developing effect of the developer solution.